Add version (release, tag) from Git to Docker Tag

[zaporylie]

I think we should start versioning our collection of docker images to allow, at some point, major (breaking) changes.

Initial release could look like this:

PHP version	Type	Docker Tag (current)	Docker Tags (new)	Git Tag
5.4	cli	5.4-cli	5.4-cli, 5.4-cli-1.0.0, 5.4-cli-1.0, 5.4-cli-1	1.0.0
5.4	fpm	5.4-fpm	5.4-fpm, 5.4-fpm-1.0.0, 5.4-fpm-1.0, 5.4-fpm-1	1.0.0
5.4	apache	5.4-apache	5.4-apache, 5.4-apache-1.0.0, 5.4-apache-1.0, 5.4-apache-1	1.0.0
5.5	cli	5.5-cli	5.5-cli, 5.5-cli-1.0.0, 5.5-cli-1.0, 5.5-cli-1	1.0.0
5.5	fpm	5.5-fpm	5.5-fpm, 5.5-fpm-1.0.0, 5.5-fpm-1.0, 5.5-fpm-1	1.0.0
5.5	apache	5.5-apache	5.5-apache, 5.5-apache-1.0.0, 5.5-apache-1.0, 5.5-apache-1	1.0.0
5.6	cli	5.6-cli	5.6-cli, 5.6-cli-1.0.0, 5.6-cli-1.0, 5.6-cli-1	1.0.0
5.6	fpm	5.6-fpm	5.6-fpm, 5.6-fpm-1.0.0, 5.6-fpm-1.0, 5.6-fpm-1	1.0.0
5.6	apache	5.6-apache	5.6-apache, 5.6-apache-1.0.0, 5.6-apache-1.0, 5.6-apache-1	1.0.0
7.0	cli	7.0-cli	7.0-cli, 7.0-cli-1.0.0, 7.0-cli-1.0, 7.0-cli-1	1.0.0
7.0	fpm	7.0-fpm	7.0-fpm, 7.0-fpm-1.0.0, 7.0-fpm-1.0, 7.0-fpm-1	1.0.0
7.0	apache	7.0-apache	7.0-apache, 7.0-apache-1.0.0, 7.0-apache-1.0, 7.0-apache-1	1.0.0

This way we could let people lock on specific release of drupal-docker/php. Of course additional tags (i.e. latest, 5, 7-cli) would still point to latest release within php branch.

[zaporylie]

Tomorrow is the last day 5.4 and 5.5 are supported. I'm gonna add this policy to drupal-docker docs and setup releases on docker hub, to have at least one release of both 5.4 and 5.5 before end of tomorrow.